Multiple time allocation and release

I am creating a quiz app for iPhone/iPad(universal app).It is working fine on simulator but on real device there are some problem i am facing..

• I am creating UILabels and UIButtons programmatically and i am using them so many times for displaying questions and answers one by one.

problem is when i reach around question 20 to 22 the application crashes. I don't know why. there is no memory leak i found. I release all the labels and buttons at the -dealloc function.

may be it happens because 22 questions takes some memory and not release till dealloc function call.

What i want is , Is there any way to release labels and buttons after every question and then it will allocate again? or any way in which i can use less memory for allocation labels and buttons??

I am using this code :

//lbl ref to btn1
ans1 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 292, 697, 100)] autorelease];
ans1.numberOfLines = 0;
ans1.font = [UIFont systemFontOfSize:26];
ans1.text = [theQuiz objectAtIndex:row+1];
ans1.lineBreakMode = UILineBreakModeWordWrap;
[ans1 sizeToFit];
//[self.view addSubview:ans1];
//lbl ref to btn2
ans2 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 312 + ans1.frame.size.height , 697, 100)] autorelease];
ans2.numberOfLines = 0;
ans2.font = [UIFont systemFontOfSize:26];
ans2.text = [theQuiz objectAtIndex:row+2];
ans2.lineBreakMode = UILineBreakModeWordWrap;
[ans2 sizeToFit];
// [self.view addSubview:ans2];
//lbl ref to btn3
ans3 = [[[UILabel alloc] initWithFrame:CGRectMake(36 ,332 + ans1.frame.size.height + ans2.frame.size.height , 697 , 100)] autorelease];
ans3.numberOfLines = 0;
ans3.font = [UIFont systemFontOfSize:26];
ans3.text = [theQuiz objectAtIndex:row+3] ;
ans3.lineBreakMode = UILineBreakModeWordWrap;
[ans3 sizeToFit];
// [self.view addSubview:ans3];
//lbl ref to btn4
ans4 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 352 + ans1.frame.size.height + ans2.frame.size.height + ans3.frame.size.height, 697, 100)] autorelease];
ans4.numberOfLines = 0;
ans4.font = [UIFont systemFontOfSize:26];
ans4.text = [theQuiz objectAtIndex:row+4];
ans4.lineBreakMode = UILineBreakModeWordWrap;
[ans4 sizeToFit];
// [self.view addSubview:ans4];

rightAnswer = [[theQuiz objectAtIndex:row+5] intValue];

Question = [[[UILabel alloc] initWithFrame:CGRectMake(22, 130, 725, 160)] autorelease];
Question.numberOfLines = 0;
//Question.font = [UIFont systemFontOfSize:27];
Question.text = [NSString stringWithFormat:@"%@" ,selected1];
Question.lineBreakMode = UILineBreakModeWordWrap;
[Question setFont:[UIFont fontWithName:@"Futura" size:26]];
Question.backgroundColor = [UIColor clearColor];
[Question sizeToFit];
[self.view addSubview:Question];

//For 1st Option.
button = [UIButton buttonWithType:UIButtonTypeCustom];
[button addTarget:self 
           action:@selector(buttonOne)
 forControlEvents:UIControlEventTouchDown];
button.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button.titleLabel.font = [UIFont systemFontOfSize:24];
[button setTitle:[theQuiz objectAtIndex:row+1] forState:UIControlStateNormal];
[button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button.frame = CGRectMake(34, 200 + Question.frame.size.height , 700, ans1.frame.size.height + 20) ;
[self.view addSubview:button];
button.layer.borderWidth = 3;
button.layer.borderColor = [[UIColor purpleColor ] CGColor];
button.layer.cornerRadius = 10.0;
[button setBackgroundImage:[UIImage imageNamed:@"buttun.png"] forState:UIControlStateNormal];
button.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);

//For 2nd Option.
button2 = [UIButton buttonWithType:UIButtonTypeCustom];
[button2 addTarget:self 
            action:@selector(buttonTwo)
  forControlEvents:UIControlEventTouchDown];
[button2 setTitle:[theQuiz objectAtIndex:row+2] forState:UIControlStateNormal];
[button2 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button2.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button2.titleLabel.font = [UIFont systemFontOfSize:24];
button2.frame = CGRectMake(34, 230 + Question.frame.size.height + button.frame.size.height , 700, ans2.frame.size.height + 20);
button2.layer.borderWidth = 3;
button2.layer.borderColor = [[UIColor darkGrayColor ] CGColor];
button2.layer.cornerRadius = 10.0;
[self.view addSubview:button2];
[button2 setBackgroundImage:[UIImage imageNamed:@"buttun2.png"] forState:UIControlStateNormal];
button2.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);

//For 3rd Option.
button3 = [UIButton buttonWithType:UIButtonTypeCustom];
[button3 addTarget:self 
            action:@selector(buttonThree)
  forControlEvents:UIControlEventTouchDown];
[button3 setTitle:[theQuiz objectAtIndex:row+3] forState:UIControlStateNormal];
[button3 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button3.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button3.titleLabel.font = [UIFont systemFontOfSize:24];
button3.frame = CGRectMake(34, 260 + Question.frame.size.height + button.frame.size.height + button2.frame.size.height , 700, ans3.frame.size.height + 20);
button3.layer.borderWidth = 3;
button3.layer.borderColor = [[UIColor purpleColor ] CGColor];
button3.layer.cornerRadius = 10.0;

[self.view addSubview:button3];
[button3 setBackgroundImage:[UIImage imageNamed:@"buttun.png"] forState:UIControlStateNormal];
button3.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);

//For开发者_如何学JAVA 4th Option.
button4 = [UIButton buttonWithType:UIButtonTypeCustom];
[button4 addTarget:self 
            action:@selector(buttonFour)
  forControlEvents:UIControlEventTouchDown];
[button4 setTitle:[theQuiz objectAtIndex:row+4] forState:UIControlStateNormal];
[button4 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button4.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button4.titleLabel.font = [UIFont systemFontOfSize:24];
button4.frame = CGRectMake(34, 290 + Question.frame.size.height + button.frame.size.height + button2.frame.size.height + button3.frame.size.height , 700, ans4.frame.size.height + 20);
button4.layer.borderWidth = 3;
button4.layer.borderColor = [[UIColor darkGrayColor ] CGColor];
button4.layer.cornerRadius = 10.0;
[self.view addSubview:button4];
[button4 setBackgroundImage:[UIImage imageNamed:@"buttun2.png"] forState:UIControlStateNormal];
button4.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);

NSString *strright = [theQuiz objectAtIndex:row+7];
//NSString *strtext = [[NSString alloc] initWithFormat:@"%@" , strright];

rightans = [[[UILabel alloc] initWithFrame:CGRectMake(50, 330, 650, 150)]autorelease];
rightans.numberOfLines = 0;
rightans.text = [NSString stringWithFormat:@"%@" , strright];
rightans.backgroundColor = [UIColor clearColor];
rightans.font = [UIFont systemFontOfSize:26];
[self.view addSubview:rightans];
[rightans sizeToFit];
[rightans setHidden:YES];

//Description.
NSString *des = [theQuiz objectAtIndex:row+6];
//  NSString *destext = [[NSString alloc] initWithFormat:@"\n> Explanation :\n%@\n\n" , des];

Description = [[[UILabel alloc] initWithFrame:CGRectMake(40, 400 + rightans.frame.size.height , 690, 150)] autorelease];
Description.numberOfLines = 0;
// Description.font = [UIFont systemFontOfSize:13.5];
Description.text = [NSString stringWithFormat:@"\n> Explanation :\n%@\n\n" , des];
[Description setFont:[UIFont fontWithName:@"Futura" size:26]];
Description.lineBreakMode = UILineBreakModeWordWrap;
Description.backgroundColor = [UIColor clearColor];
[Description sizeToFit];
[self.view addSubview:Description];
[Description setHidden:YES];


ContainerView = [[UIView alloc] initWithFrame:CGRectMake(30, 400 + rightans.frame.size.height , 700 ,Description.frame.size.height)];
ContainerView.backgroundColor = [UIColor clearColor];
ContainerView.layer.cornerRadius = 10.0;
ContainerView.layer.borderColor = [[UIColor grayColor] CGColor];
ContainerView.layer.borderWidth = 3;
// [ContainerView addSubview:Description];
[self.view addSubview:ContainerView];
[ContainerView setHidden:YES];

Any help??

Thank you.

You should not release autorelease objects.

1. Once you add label as subview to the view - the view will retain the label you can release the label, In your case you are not releasing ContainerView
2. You should not release the autoreleased objects - it is fine

Firstly, you should release an object as soon as you add it to a view using [self.view addSubview: myObj]. When you add an object like this, its retain count is incremented by the parent view & you should release it (to decrement its retain count) to allow its garbage collection. Your code should be like-

[self.view addSubview: myObj];
[myObj release];

Secondly, do you have the crash log?

HTH,

Akshay

1) Simple rule, you release whatever you alloced or retained, copied...All other variable you have will be autoreleased. In your code you are allocing all labels, but not Buttons.. You must release all Labels after adding it to subView. Buttons you just add to subView, not release afterwords as you are not allocating it.. Since you are asking similiar question for 2 days I just worked on your code

//lbl ref to btn1
ans1 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 292, 697, 100)] autorelease];
ans1.numberOfLines = 0;
ans1.font = [UIFont systemFontOfSize:26];
ans1.text = [theQuiz objectAtIndex:row+1];
ans1.lineBreakMode = UILineBreakModeWordWrap;
[ans1 sizeToFit];
[self.view addSubview:ans1];


//lbl ref to btn2
ans2 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 312 + ans1.frame.size.height , 697, 100)] autorelease];
ans2.numberOfLines = 0;
ans2.font = [UIFont systemFontOfSize:26];
ans2.text = [theQuiz objectAtIndex:row+2];
ans2.lineBreakMode = UILineBreakModeWordWrap;
[ans2 sizeToFit];
[self.view addSubview:ans2];


//lbl ref to btn3
ans3 = [[[UILabel alloc] initWithFrame:CGRectMake(36 ,332 + ans1.frame.size.height + ans2.frame.size.height , 697 , 100)] autorelease];
ans3.numberOfLines = 0;
ans3.font = [UIFont systemFontOfSize:26];
ans3.text = [theQuiz objectAtIndex:row+3] ;
ans3.lineBreakMode = UILineBreakModeWordWrap;
[ans3 sizeToFit];
[self.view addSubview:ans3];


//lbl ref to btn4
ans4 = [[[UILabel alloc] initWithFrame:CGRectMake(36, 352 + ans1.frame.size.height + ans2.frame.size.height + ans3.frame.size.height, 697, 100)] autorelease];
ans4.numberOfLines = 0;
ans4.font = [UIFont systemFontOfSize:26];
ans4.text = [theQuiz objectAtIndex:row+4];
ans4.lineBreakMode = UILineBreakModeWordWrap;
[ans4 sizeToFit];
[self.view addSubview:ans4];

rightAnswer = [[theQuiz objectAtIndex:row+5] intValue];

Question = [[[UILabel alloc] initWithFrame:CGRectMake(22, 130, 725, 160)] autorelease];
Question.numberOfLines = 0;
//Question.font = [UIFont systemFontOfSize:27];
Question.text = [NSString stringWithFormat:@"%@" ,selected1];
Question.lineBreakMode = UILineBreakModeWordWrap;
[Question setFont:[UIFont fontWithName:@"Futura" size:26]];
Question.backgroundColor = [UIColor clearColor];
[Question sizeToFit];
[self.view addSubview:Question];

//For 1st Option.
button = [UIButton buttonWithType:UIButtonTypeCustom];
[button addTarget:self action:@selector(buttonOne) forControlEvents:UIControlEventTouchDown];
button.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button.titleLabel.font = [UIFont systemFontOfSize:24];
[button setTitle:[theQuiz objectAtIndex:row+1] forState:UIControlStateNormal];
[button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button.frame = CGRectMake(34, 200 + Question.frame.size.height , 700, ans1.frame.size.height + 20) ;
button.layer.borderWidth = 3;
button.layer.borderColor = [[UIColor purpleColor ] CGColor];
button.layer.cornerRadius = 10.0;
[button setBackgroundImage:[UIImage imageNamed:@"buttun.png"] forState:UIControlStateNormal];
button.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);
[self.view addSubview:button];



//For 2nd Option.
button2 = [UIButton buttonWithType:UIButtonTypeCustom];
[button2 addTarget:self action:@selector(buttonTwo) forControlEvents:UIControlEventTouchDown];
[button2 setTitle:[theQuiz objectAtIndex:row+2] forState:UIControlStateNormal];
[button2 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button2.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button2.titleLabel.font = [UIFont systemFontOfSize:24];
button2.frame = CGRectMake(34, 230 + Question.frame.size.height + button.frame.size.height , 700, ans2.frame.size.height + 20);
button2.layer.borderWidth = 3;
button2.layer.borderColor = [[UIColor darkGrayColor ] CGColor];
button2.layer.cornerRadius = 10.0;
[button2 setBackgroundImage:[UIImage imageNamed:@"buttun2.png"] forState:UIControlStateNormal];
button2.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);
[self.view addSubview:button2];


//For 3rd Option.
button3 = [UIButton buttonWithType:UIButtonTypeCustom];
[button3 addTarget:self action:@selector(buttonThree) forControlEvents:UIControlEventTouchDown];
[button3 setTitle:[theQuiz objectAtIndex:row+3] forState:UIControlStateNormal];
[button3 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button3.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button3.titleLabel.font = [UIFont systemFontOfSize:24];
button3.frame = CGRectMake(34, 260 + Question.frame.size.height + button.frame.size.height + button2.frame.size.height , 700, ans3.frame.size.height + 20);
button3.layer.borderWidth = 3;
button3.layer.borderColor = [[UIColor purpleColor ] CGColor];
button3.layer.cornerRadius = 10.0;
[button3 setBackgroundImage:[UIImage imageNamed:@"buttun.png"] forState:UIControlStateNormal];
button3.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);
[self.view addSubview:button3];



//For 4th Option.
button4 = [UIButton buttonWithType:UIButtonTypeCustom];
[button4 addTarget:self action:@selector(buttonFour) forControlEvents:UIControlEventTouchDown];
[button4 setTitle:[theQuiz objectAtIndex:row+4] forState:UIControlStateNormal];
[button4 setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button4.titleLabel.lineBreakMode = UILineBreakModeWordWrap;
button4.titleLabel.font = [UIFont systemFontOfSize:24];
button4.frame = CGRectMake(34, 290 + Question.frame.size.height + button.frame.size.height + button2.frame.size.height + button3.frame.size.height , 700, ans4.frame.size.height + 20);
button4.layer.borderWidth = 3;
button4.layer.borderColor = [[UIColor darkGrayColor ] CGColor];
button4.layer.cornerRadius = 10.0;
[button4 setBackgroundImage:[UIImage imageNamed:@"buttun2.png"] forState:UIControlStateNormal];
button4.titleEdgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);
[self.view addSubview:button4];



NSString *strright = [theQuiz objectAtIndex:row+7];
//NSString *strtext = [[NSString alloc] initWithFormat:@"%@" , strright];



rightans = [[[UILabel alloc] initWithFrame:CGRectMake(50, 330, 650, 150)]autorelease];
rightans.numberOfLines = 0;
rightans.text = [NSString stringWithFormat:@"%@" , strright];
rightans.backgroundColor = [UIColor clearColor];
rightans.font = [UIFont systemFontOfSize:26];
[rightans sizeToFit];
[rightans setHidden:YES];
[self.view addSubview:rightans];


//Description.
NSString *des = [theQuiz objectAtIndex:row+6];
//  NSString *destext = [[NSString alloc] initWithFormat:@"\n> Explanation :\n%@\n\n" , des];


Description = [[[UILabel alloc] initWithFrame:CGRectMake(40, 400 + rightans.frame.size.height , 690, 150)] autorelease];
Description.numberOfLines = 0;
// Description.font = [UIFont systemFontOfSize:13.5];
Description.text = [NSString stringWithFormat:@"\n> Explanation :\n%@\n\n" , des];
[Description setFont:[UIFont fontWithName:@"Futura" size:26]];
Description.lineBreakMode = UILineBreakModeWordWrap;
Description.backgroundColor = [UIColor clearColor];
[Description sizeToFit];
[Description setHidden:YES];
[self.view addSubview:Description];



ContainerView = [[UIView alloc] initWithFrame:CGRectMake(30, 400 + rightans.frame.size.height , 700 ,Description.frame.size.height)];
ContainerView.backgroundColor = [UIColor clearColor];
ContainerView.layer.cornerRadius = 10.0;
ContainerView.layer.borderColor = [[UIColor grayColor] CGColor];
ContainerView.layer.borderWidth = 3;
// [ContainerView addSubview:Description];
[ContainerView setHidden:YES];
[self.view addSubview:ContainerView];
[ContainerView release];

Some other points of note.

1) A variable name should always start with a small letter.. It is not a written rule, but a good practice, easier for yourself and for others (like us) reviewing it. Variable name like "Description" and "Question" are not good.

2) Never repost your question.. If you just formatted the code better, you should have got answer in your previous question itself..